feat(expressions): add support for multi-statement expressions

hsp/expressions/manipulator.js

@@ -59,6 +59,7 @@ module.exports = function(input, inputTree) {
                 evaluator(tree.l, scope)[evaluator(tree.r, scope)] = newValue;
             }
         },
-        isAssignable : isAssignable
+        isAssignable: isAssignable,
+        isMultiStatement: tree instanceof Array
     };
 };

hsp/expressions/parser.js

@@ -284,16 +284,22 @@ function expression(rbp) {
  * @return {Object} - parsed AST
  */
 module.exports = function (input) {
+    var expr, exprs = [];
 
     tokens = lexer(input);
     token = undefined;
     tokenIdx = 0;
 
     if (tokens.length) {
         advance(); //get the first token
-        var expr = expression(0);
-        advance('(end)'); //make sure that we are at the end of an expression
-        return expr;
+        while(token.id !== '(end)') {
+            expr = expression(0);
+            exprs.push(expr);
+            if (token.v === ',') {
+                advance(',');
+            }
+        }
+        return exprs.length === 1 ? exprs[0] : exprs;
     } else {
         return {f: 0, a: 'literal', v: undefined};
     }

test/expressions/manipulator.spec.js

@@ -259,6 +259,19 @@ describe('getValue', function () {
         expect(expression("{foo: 'bar', foo2: 'baz'}").getValue({})).to.eql({foo: 'bar', foo2: 'baz'});
         expect(expression("{foo: {foo2: 'baz'}}").getValue({})).to.eql({foo: {foo2: 'baz'}});
     });
+
+    describe('multiple statements in an expression', function () {
+
+        it('should allow multiple comma-separated statements', function () {
+            expect(expression("foo, bar").getValue({foo: 'foo', bar: 'bar'}))
+                .to.eql(['foo', 'bar']);
+        });
+
+        it('should mark expressions as multi-statement', function () {
+            expect(expression("foo, bar").isMultiStatement).to.be.ok();
+            expect(expression("foo").isMultiStatement).to.not.be.ok();
+        });
+    });
 });
 
 describe('forgiving evaluation of expressions', function () {